Paddy Lowe, Chief Technical Officer: Firstly I want to congratulate Robert on his first official F1 session since he left the sport at the end of 2010. He did a fantastic job for us today, and it is a great credit to his determination and character that we have seen his return to F1. I'm only sorry that the car we gave him for FP1 was extremely difficult. But he did the very best job possible and provided valuable feedback. Overall it was not a good day. We didn't expect this to be a strong circuit for us, given the problems we've been having with the FW41 all year, but our pace is worse than we predicted. The underlying problems are understood and will be fixed in due course. On top of that we are struggling with the supersoft tyre in particular on this track. Nevertheless, we made some progress between FP1 and FP2 and I'm sure we can do much more overnight to find a better balance for qualifying and the race.

Lance Stroll: I didn't really run this morning, as I went off on my second push lap so it was not the morning I was hoping for. It was very difficult to understand the balance as it's definitely not the balance a racing driver wants to feel. This afternoon we tried to sort out a few things and the car improved a little bit, but still there is so much to understand and figure out. There is a lot of work to be done tonight and we have got to understand what to do so we can be better.

Sergey Sirotkin: The car is difficult to drive, and mentally it makes you concentrate 200% on everything because it's so tricky. You saw this morning how difficult it was with cars going off. It takes a lot of energy from you just to drive. We didn't expect it to be easy and I'm waiting for the chance to test most of the new bits on our car. Yes, that was a bad session, but we have a long-term plan with a lot of effort from all of us, so I don't want one bad session or event to affect it. Everyone is working flat out and it will take time, but we will get there.

Robert Kubica: It is a good feeling - not so much from being in the car but from before that, because I'm back driving in an official session, even if it's only FP1. It's the first time since the end of 2010 so there's some emotion, but this disappeared very soon as we have quite a difficult car to drive. The balance was quite off, but somehow we have to stick to what we've got to complete our aero tests and evaluations. It wasn't an easy session, but we managed in difficult conditions and I was able to give some good feedback. When you're struggling so much it's difficult to enjoy it, but still I'm happy because I think the most difficult car we've had was in this session and I managed to stay cool, and somehow extract what I thought was a reasonable level of performance. I think I can be happy as I did what I was asked to do.

Check out our Friday gallery from Barcelona, here.